1. Technical Field
This invention relates generally to inductively energized electrodeless gas discharge lamps and more particularly to the manufacture and assembly of the sealed envelope and the surrounding external induction coil of such lamps.
2. Related Prior Art
Electrodeless gas discharge lamp assemblies are well known in which a gas, such as neon, is sealed within a light-transmitting envelope of quartz or the like and surrounded by an external induction coil. The coil, when energized, excites the gas to discharge illumination.
The coil of such assemblies is often larger in diameter than that of the envelope such that a gap exists between the envelope and coil. Such gap can be eliminated by disposing the coil in intimate contact with the outer surface of the envelope. Known techniques for achieving such intimate contact of the coil include winding a strand of copper wire or the like about the envelope or printing a metallic coil pattern on the outer surface of the envelope. Direct engagement between the coil and envelope minimizes any losses of inductance that may be attributed to the presence of gap, since the flux lines generated by the coil are sure to pass through the envelope and avoid any gap.
The winding of the coil about the envelope requires special fixturing to support the envelope and adds a costly manufacturing step to the assembly process. Screen printing the coil onto the envelope likewise requires special, costly printing equipment and techniques and introduces a manufacturing step to the assembly process. This invention is directed toward providing a more efficient, cost-effective approach to preparing and assembling the envelope and coil to achieve the desired close contact therebetween.